1. Field of the Invention
The invention is directed to a composting system for the production of compost of different degrees of ripeness by means of repeated rearrangement of the layers of a tabular stack comprising a layer rearranging unit which is movable longitudinally and transversely over the surface of the rotting matter, as well as to a composting method.
2. Background Prior Art
Compost production went has gone through a number of marked phases of development. Composting has been a favorite pastime of the garden owner since the start of this century. These garden owners put garden and kitchen waste, as valuable materials, back into the natural cycle again. The building up and rearrangement of the layers of the compost stacks is effected manually, wherein a great number of methods, ingredients, time cycles, etc. have been and are presently being devised and recommended.
The pressure to reclaim so-called "waste" collected by the public which is suitable for composting soon forced a mechanization for the large quantities of compost which could no longer be managed manually. After the war, there developed a tendency to use devices resembling construction machinery for the production and rearrangement of layers of the stacks, even in the form of known tractor shovels.
Since the ripening of compost is a predominantly biological process, a corresponding failure was "preprogrammed", as it were, by the mechanized approach and corresponding handling of compost materials with tractor shovels. The compost soil obtained was for the most part so unacceptable that in many places the public to this day refuses to produce compost.
Subsequently, technical circles made efforts to find a biologically more expedient preparation of compost. In order to keep process costs low, a multitude of intensively forced biological decomposition processes were developed. However, the proposed bio-reactors were not widely used.
The recent past has been characterized by two solutions, analogous in themselves. The first, more for small plants, again makes use of the long-known triangular stacks. Layers are rearranged in the latter with shifting equipment. In so doing, any unnecessary pressing of the product is avoided; on the contrary, the product is loosened anew every time it is shifted. The great advantage to this method consists in that the compost system maintenance personnel can influence the course of rotting to a great extent just as expediently by means of selecting the height of the stacks, layer rearranging cycles, water supply, mixing with different materials, etc. However, this advantage is simultaneously also a chief disadvantage. Optimal management of rotting matter places great demands on the responsible technicians in charge of management and accordingly requires a high level of training. As is known, the working conditions in the environment of the rotting matter are unpleasant, particularly because of the odor, so that there are few cases in which persons possessing the necessary professional requirements are also prepared to do this work. The persons must possess either great practical talent, e.g. an experienced gardener, or extensive knowledge of biology. Present efforts consist in producing compost in a biologically correct manner, but in an extensively mechanized manner. The objection is raised that the corresponding mechanical solutions, e.g. according to EP-PS 250 617, do not adequately take into account the biological cycles. The biological process during the main rotting results in a reduction in volume of up to 50% within several weeks. The emission of odors must be prevented particularly when systems are erected in the neighborhood of human settlements. This requires a complete enclosure of the composting system as well as cleaning of the exhaust air. For improved control of the biological decomposition, it is often advantageous to aerate the rot system in addition, so that such plants require relatively large investment. If the primary stack is piled up e.g. to a height of 2.5 m in the first area of the rotting matter, the rot loss results in a stack height of 1.25 m when the compost is ripe. In this way, poor use is made of the expensively enclosed space. Accordingly, this type of mechanized operation has the same disadvantages with respect to the aforementioned mechanical rearrangement of layers by the system maintenance personnel.
The invention has the object of avoiding the disadvantages of the known solutions, particularly of making possible a favorable specific utilization of surface area with operation which is as completely automatic as possible with simultaneous optimal biological management of the compost ripening. What is desired is an optimal combination of the best scientific knowledge on the one hand with the more empirical experience of practical technical personnel.
The solution, according to the invention, is characterized in that the layer rearranging unit is constructed as a conveyor system which can be changed with respect to length and can be moved over the rotting matter in the manner of a crane in such a way that the working distance between the working and ejection locations is changeable and is selectable via a control, wherein the working device comprises working means which work in an upward direction and can be raised and lowered.
The present invention meets this object with surprisingly simple means in a manner previously considered impossible. As is known, any use of automation in biological processes is of little use or is only harmful when the occurring biological processes and physical consequences are not adequately taken into account. A programming only makes sense when the means used for carrying it out can be used in a correspondingly directed manner with respect to their manner of operation. It is precisely this point which is first made possible with the present invention in that the working and ejection locations are freely selectable within a required range of choice by means of the longitudinal displaceability of the conveyor system. However, a particular advantage of the invention accordingly consists in that the rearrangement of layers of the rotting matter is controllable according to a predetermined plan, particularly in such a way that e.g. the rot loss can be compensated for automatically, that is, the collapsed "old stack" can be piled up again to a height like that at the beginning.
Optimal programs according to season and product can be repeated at any time and a continuous improvement of the monitoring of the ripening process is achieved in this way. Depending on the throughput capacity determined by the rotting, season, product humidity and temperature, etc., a determined basic program can be entered and continuously adapted to the instantaneous given conditions in operation, whether this be a matter of adjusting the time cycle, optimizing the supply air or irrigation quantities, or completely utilizing the maximum height when there is a great amount of raw material. Corresponding programs can be designed in such a way that the rot can act as a buffer for fluctuations from one delivery quantity to another, wherein the flow can be influenced at any time by direct intervention of the system maintenance personnel. The "product handling" is effected in an extremely careful manner in that the working elements work with conveyor means operating in an upward direction. This results in a loosening of the material. The material is lifted with the slightest possible pressure, displaced horizontally and released in a downward direction. The conveyors can be inclined, in particular a first conveyor which takes over the rotting matter from the working elements. It is essential that the ejection is horizontally displaceable independent of the working location at least in one conveyor. For reasons relating to energy as well as for practical considerations, every unnecessary vertical conveying and, in the ejection location, every unnecessary drop height should be avoided. In general, the working is effected from the bottom to the top, the erection of the following stack is effected from the top.
The invention allows a number of particularly advantageous design ideas. For example, a shifting area between the working and ejection locations is selected within Lmin and Lmax by means of the longitudinal displaceability of the conveyor system, wherein the ratio Lmin:Lmax is 1:1.2 to 1:3, preferably 1:1.5 to 1:2.5, particularly preferably approximately 1:2.
Accordingly, in most cases, the rot loss can be completely compensated for in that the material is brought from a great distance and then piled up higher again. A particularly great number of practical advantages result when two horizontal conveyors are provided which are longitudinally displaceable relative to one another.
The rotting matter working device can be constructed as an upwardly conveying scraper conveyor. In this design idea all horizontal conveyors can actually be installed in a horizontal position, which is simpler in terms of construction for longitudinal displacement. It is particularly preferred that the rotting matter working device be constructed as a bucket conveyor, particularly as digging and conveyor wheels working in an upward direction. At present the optimal form for garden waste, household compost and leaf material consists therein; the rotting matter working device is preferably constructed as a double-digging and conveyor wheel. On the other hand, a scraper conveyor is more suitable when largely vegetable materials which tend to cling together must be processed.
It is further suggested with the new invention solution to provide a continuous-flow weighing system for the rotting matter in the area of the horizontal conveyor, wherein this is constructed as a continuous-flow weighing system or as a belt weigher. The belt weigher can be integrated in a horizontal conveyor.
The weighing system simultaneously has several great advantages. In addition to measuring humidity, it serves as the main element of the sensing arrangement for an accurate feeding of water. Further, it reinforces the automatic monitoring of the system, since the latter can normally be operated without operators. The rearrangement of layers can be monitored together with the respective layer rearranging performance by means of measuring the power consumption for the working device. It is advantageous that a continuous water content measuring device be assigned, as well as a liquid feed device for controlled addition of liquid. The liquid feed is advisably effected in the area of the ejection location.
Another substantial design idea consists in that the ejection location is constant in the longitudinal direction in an end area of the rotting system and the working location is selectable according to the working process. In this way one of the most important advantages of the new invention solution is usable not only in the rearrangement of layers, but likewise when discharging from the rotting system.
The rotting matter is defined in a manner known per se by two longitudinal walls, and the rotting matter working device, with the horizontal conveyor as layer rearranging unit, is longitudinally and transversely movable in the manner of a crane according to the preselected program. It is further suggested that the floor of the rot system comprise a plurality of individually controllable ventilation fields, that the rot system be roofed in, and that the exhaust air from the rot system can be cleaned via a bio-filter. All of the rotting matter can accordingly be monitored completely automatically. Human intervention in the interior is only necessary sporadically, during disturbances, for checking and for all kinds of adjustments. The system maintenance personnel can intervene at any time according to their judgement. Scientific knowledge can be made use of at any time for periodic improvement of the basic programming.
The invention is further directed to a new composting method for the automatic production of compost, wherein the rearrangement of layers and the discharge of the compost is effected along the rotting matter location in the manner of a crane and is characterized in that the working and ejection locations are programmable along the rotting matter location in the transverse and longitudinal directions in such a way that the rotting cycle is optimized according to the throughput capacity and rotting time, and the rot loss can be successively compensated for in such a way that the entire process is controllable in a fully automatic manner.
It is especially preferable that the building up of the rotting matter and the primary stack, respectively, likewise be controlled, but this is effected using independent mechanical means.